This invention relates generally to air conditioning equipment and more particularly to apparatus for draining the condensate from a condensate pan associated with the fan coil of an air conditioning system.
In the normal operation of an air conditioning system, the evaporator or fan coil tends to be at temperatures below the dew point of the surrounding air. The resulting condensation is collected in a pan located under the coil, with the pan then being drained off to an appropriate disposal site such as a sewer drain or to the ground outside.
Because of a low pressure condition that is created by the operation of the fan inside the unit, it has become conventional practice to provide a P-trap to prevent the inward flow of air through the drainage pipe, which flow of air would otherwise tend to prevent the flow of condensate from the condensate pan. In addition, the P-trap acts to isolate the system from the backflow of odors that would otherwise occur when the system is connected to discharge condensate directly to the sewer.
In some air conditioning systems it is not convenient to locate the evaporator coil near the P-trap, which is conventionally located just outside the cabinet. For example, in a packaged system, wherein both the outdoor and the indoor sections are located within a single cabinet, in order to accommodate all of the necessary components within the cabinet, it may be desirable to locate the evaporator coil and associated condensate pan at some distance from the cabinet panel. The pan is then commonly interconnected to the P-trap by way of a condensate hose that runs substantially horizontally between the two components. With the use of such a condensate hose, it has been found that, under certain operating conditions, the condensate will not flow through the length of the condensate hose and will therefore accumulate in the condensate pan to the point where the pan will overflow and wet the insulation material therebelow and eventually cause damage to the insulation and loss of efficiency in the system. For example, it has been found that with the use of a large blower that produces high static pressures, the negative pressures surrounding the coil tend to prevent the condensate from flowing through the entire length of the condensate hose to the P-trap. Similarly, it has been found that resistance to flow is also caused by water turbulence in the condensate pan as occurs by the fan-created air motion above the pan. lt has also been observed by the inventors that the resistance to flow within the condensate hose may be affected by other things such as the close proximity of the coil itself to the discharge drain in the condensate pan or a partial restriction at the entrance of the condensate hose.
In all such cases, the ultimate cause of the failure of condensate to drain from the condensate pan is seen by the inventors to be the trapping of a volume of air between the flow of water from the pan and the P-trap.
It is therefore an object of the present invention to provide an improved condensate disposal system for an air conditioning apparatus.
Another object of the present invention is the provision in an air conditioning system for ensuring proper condensate drainage under all operating conditions.
Yet another object of the present invention is the provision for ensuring the proper flow of condensate through a condensate hose connecting a condensate pan and a P-trap.
Still another object of the present invention is a provision for a condensate disposal system which is economical to manufacture and effective in use.
These objects and those other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.